1. Field of the Invention
The present invention relates to the field of signal processing and, more particularly, to a method and apparatus for adaptively compressing, transmitting, and reconstructing signals.
2. Description of the Related Art
Many communications systems have limited transmission bandwidths. These systems often do not perform adequately in view of the ever growing need to send more information quickly and economically. Some systems use inefficient methods that lead to a loss in the quality of the transmitted data. In other instances, systems are replaced with new equipment or use extra power to handle the increased demand for bandwidth or speed. However, many users cannot afford to replace their system's components or use more power. Some systems with limited bandwidth (such as a space to ground communication system) use signal compression to overcome limited bandwidth when transmitting signals.
Compression is the reduction in the size of data in order to save space or transmission time. For example, in a data transmission, compression can be performed on the data content or on the entire transmission unit (including header data) depending on the type of compression. Content compression on data transmission may be as simple as removing all “extra space” characters, inserting a single repeat character to indicate a string of repeated characters, or substituting smaller bit strings for frequently occurring characters. Compression typically is performed by a predefined formula or algorithm that determines how to compress the data. When a compressed signal is received, the signal typically is reconstructed or decompressed to its original or near-original form using the same formula or algorithm.
In some communication systems, typical compression techniques maximize the efficiency of the data transmission. However, many of these techniques do not apply to certain types of systems, such as wideband signal collection systems where an unknown wideband spectrum is digitized. In these types of systems, alternative signal compression techniques are not common. Accordingly, there is a need for a method of signal compression that is efficient, inexpensive, applicable to a variety of systems that receive wideband unknown signals and uses less power.